# coding=utf-8
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import logging
import time

import psutil

from lvestats.eventloop.plugin_executors import (
    DbRecoveredException,
    DbRecoverFailedException,
    PluginExecutionException,
    PluginTimeoutException,
    SameProcessPluginExecutor,
    SeparateProcessPluginExecutor,
)
from lvestats.lib.config import ConfigError

__author__ = 'iseletsk'


class MainLoop(object):
    def __init__(self,
                 config,
                 interval=5,
                 plugins=None,
                 plugin_timeout=5,
                 multiproc=True,
                 profiling_log=None):
        """
        :param config:
        :param lve_data: data being collected, used and modified by plugins during main loop execution.
        :param interval: update interval in seconds
        :param plugins: list of plugins
        :param plugin_timeout: time in seconds to let plugin be executed
        :param str profiling_log: if not None -- file to write profiling info
        :return:
        """
        self.config = config
        self.interval = interval
        self.default_interval = interval
        self.do_exit = False
        if plugins is None:
            self.plugins = []
        else:
            self.plugins = plugins

        self.aggregation_period = config.get('aggregation_period', 60)

        self.default_user_plugin_timeout = plugin_timeout
        self.log = logging.getLogger('main.loop')
        if multiproc:
            self.executor = SeparateProcessPluginExecutor(config, profiling_log)
        else:
            self.executor = SameProcessPluginExecutor(config)

        self.profiling_log = profiling_log

    def exit(self):
        self.log.debug('Want to exit')
        self.do_exit = True

    @staticmethod
    def _plugin_path_name(plugin_class):
        """
        >>> from lvestats.plugins.generic.aggregators import LveUsageAggregator
        >>> plugin_class = LveUsageAggregator
        >>> MainLoop._plugin_path_name(plugin_class)
        :param plugin_class:
        :return: Filesystem path to plugin and it's name
        """
        import inspect  # pylint: disable=import-outside-toplevel
        path = inspect.getfile(plugin_class)
        path = path.replace('.pyc', '.py')
        name = plugin_class.__name__
        return path, name

    def get_debug_info(self, stat_getter):
        try:
            stat_value = stat_getter()
            return str(stat_value)
        except Exception as e:
            self.log.debug('Error while getting info: %s', str(e))
            return ''

    def run(self, times=None):
        cnt = None
        if times:
            cnt = times

        profiler = None
        if self.profiling_log:
            import cProfile  # pylint: disable=import-outside-toplevel
            profiler = cProfile.Profile()
            if not cnt:
                cnt = 10
            self.log.info('Profiling server for %s plugin cycles', cnt)
            profiler.enable()

        while True:
            now = time.time()
            for plugin in self.plugins:
                if self.do_exit:
                    self.log.debug('Exiting')
                    self.executor.terminate()
                    return

                if getattr(plugin, '__is_user_plugin__', False):
                    timeout = getattr(plugin, 'timeout', self.default_user_plugin_timeout)
                else:
                    timeout = getattr(plugin, 'timeout', None)

                try:
                    if profiler:
                        profiler.runcall(self.executor.execute, plugin, now, timeout)
                    else:
                        self.executor.execute(plugin, now, timeout)
                except DbRecoveredException:
                    self.log.warning("Db was corrupt, recovered")
                    continue
                except DbRecoverFailedException:
                    self.log.exception("Unable to recover database")
                    return
                except PluginTimeoutException:
                    load = {
                        'process_count': self.get_debug_info(lambda: len(psutil.pids())),
                        'cpu': self.get_debug_info(psutil.cpu_times_percent),
                        'mem': self.get_debug_info(lambda: psutil.virtual_memory().percent),
                        'io': self.get_debug_info(psutil.disk_io_counters)
                    }
                    path, name = MainLoop._plugin_path_name(plugin)
                    self.log.error("Plugin %s:%s timed out", path, name, extra={'data': load})
                    continue
                except PluginExecutionException:
                    path, name = MainLoop._plugin_path_name(plugin)
                    self.log.exception("Error during execution of %s:%s", path, name)
                    continue
                except ConfigError:
                    path, name = MainLoop._plugin_path_name(plugin)
                    self.log.exception("Unable to init plugin %s:%s", path, name)

            if cnt:
                cnt -= 1
                if cnt == 0:
                    break
            self._sleep(now)

        if profiler:
            self.log.info('Profiling finished')
            import pstats  # pylint: disable=import-outside-toplevel
            with open(self.profiling_log, 'a+', encoding='utf-8') as f:
                f.write('Main loop profile, internal time:\n')
                stats = pstats.Stats(profiler, stream=f)
                stats.sort_stats('time').print_stats(20)

                f.write('Main loop profile, cumulative time:\n')
                stats.sort_stats('cumulative').print_stats(20)

        self.executor.terminate()

    def _sleep(self, now):
        time_passed = time.time() - now
        pause = self.interval - time_passed
        if pause > 0:
            if self.interval > self.default_interval:
                self.interval -= 0.5
            time.sleep(pause)
        else:
            if self.interval < self.aggregation_period:
                self.interval += 0.5